I am always on the lookout for movies to show in math class. The history and English teachers are always watching movies. It’s only fair that math teachers get to watch something once in a while… (So if you know of any, feel free to post a comment.)

Holes, based on the book by Louis Sachar, is about Stanley Yelnats who is sent to Camp Green Lake for a crime he didn’t commit. He is really there because of his family curse brought on by his “dirty-rotten-no-good-pig-stealing great-great-grandfather.” (I think I got the quote right. My copy of the movie is at school.)

At camp he digs holes “to build character.” He also learns more about his family curse as well as the curse on Camp Green Lake…

It’s a great movie even without the math connections. But here are some ideas for practice in algebra. (The last questions even lead into the concept of the derivative.)

One question you can ask before watching the movie:

How much dirt is in a hole that is five feet deep with a diameter of 5 feet?

Answer:

None! There is no dirt in the hole after it is dug… Haha!

Here are some more serious questions to get your students thinking about algebra. If these are too difficult, specify the length of the shovel.

The character X-Ray uses a shorter shovel than the others so he gets to dig smaller holes. Each hole has a diameter of one shovel length and a depth of one shovel length.

If his shovel is 10 percent shorter than the others, how much less dirt does he have to shovel?

If his shovel is 20 percent shorter, how much less dirt does he have to shovel?

What if it is x percent shorter?

For small percentages, is there a linear approximation to the previous question?

At what percentage does the linear approximation no longer work?

As I think of additional questions I will add them. If you can think of any feel free to post them in a comment.

Update: There are other educational resources related to Holes at eduscapes and at The Hole Truth.

Update II: Here are links to Amazon’s pages for the movie: